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Visualise surface normals

This commit is contained in:
K Tyl 2020-06-06 03:54:05 +01:00
parent c4eb43a6f3
commit a7268a2a83
1 changed files with 30 additions and 3 deletions
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33
src/main.cpp
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@ -8,12 +8,39 @@ const double ASPECT_RATIO = 16.0 / 9.0;
const int WIDTH = 384;
const int HEIGHT = static_cast<int>(WIDTH / ASPECT_RATIO);
double hitSphere(const point3& centre, double radius, const ray& r)
{
vec3 oc = r.origin() - centre;
auto a = r.direction().lengthSquared();
auto halfB = dot(oc, r.direction());
auto c = oc.lengthSquared() - radius*radius;
auto discriminant = halfB*halfB - a*c;
if (discriminant < 0)
{
return -1.0;
}
else
{
return (-halfB - sqrt(discriminant)) / a;
}
}
colour rayColour(const ray& r)
{
vec3 unitDirection = unitVector(r.direction());
double t = 0.5 * (unitDirection.y() + 1.0);
auto t = hitSphere(point3(0,0,-1), 0.5, r);
if (t > 0.0)
{
vec3 N = unitVector(r.at(t) - vec3(0,0,-1));
return 0.5*colour(N.x()+1, N.y()+1, N.z()+1);
}
auto a = colour(1.0, 1.0, 1.0);
vec3 unitDirection = unitVector(r.direction());
t = 0.5 * (unitDirection.y() + 1.0);
auto a = colour(1.0, 0.5, 0.6);
auto b = colour(0.0, 0.0, 0.0);
return lerp(a, b, t);